$\dfrac{1}{12} - \dfrac{4}{5} = {?}$
Answer: $ = {\dfrac{1 \times 5}{12 \times 5}} - {\dfrac{4 \times 12}{5 \times 12}} $ $ = {\dfrac{5}{60}} - {\dfrac{48}{60}} $ $ = \dfrac{{5} - {48}}{60} $ $ = -\dfrac{43}{60}$